Push your chair back from your desk. Put your feet flat on the floor, cross your arms and bend at the waist until your chest rests on your upper thighs and your crossed arms fall in front of your knees. Your forearms should brush your shins. Hold for 5 seconds, then rise up slowly. Repeat 5 times. Don’t do this exercise if you have a known disc problem or low back injury.
Got Something More Advanced?
Lower your chest to your upper thighs as described above, then put your hands flat on the floor. Slowly stand up, keeping your hands on the floor. You should feel a good stretch in your low back and hamstrings (the backs of your legs). Don’t overdo this stretch—stop when you feel a mild stretch—never stretch to the point of pain.